In many manufacturing applications, particularly in food processing, it is highly desirable to interleave the finished articles with thin, flexible sheets of paper, waxed paper, cellophane, plastic film, or other very thin, flexible material. For example, in packaging meat slices or hamburger patties, individual sheets of paper, waxed paper or like material inserted between adjacent pieces of meat prevent the meat from sticking together and preserve the integrity of the individual meat pieces. The same situation is presented with stacks of sliced cheese; the cheese slices tend to “grow” back together unless the slices are separated by sheets of thin, flexible material.
Often, in the basic processing equipment, there is some stage of operation at which the individual hamburger patties or other such articles traverse a given discharge path, usually terminating at a stacking position; the preferred technique is to suspend individual sheets of waxed paper or the like at some intermediate position on the path so that each article, moving along the path, picks up a sheet of paper and comes to rest in a stack in which the articles are interleaved one-for-one with the paper sheets.
U.S. Pat. Nos. 3,126,683; 2,877,120, 3,675,387 and 4,054,967 all describe variations of sheet interleaving machines.
U.S. Pat. No. 3,952,478 describes a sheet applicator for a patty-forming apparatus wherein the patty-forming apparatus includes a reciprocating mold plate that moves linearly from a fill position to a knock out position. At the knock out position, patties are removed from the mold plate in a downward direction though a discharge path. The sheet applicator interleaves individual, thin, flexible sheets of paper, cellophane, plastic film or like material with a series of hamburger patties or like flat, relatively thick articles as the articles traverse the discharge path in sequential spaced relation to each other, the path terminating at a stacking position.
The sheet applicator comprises a vacuum transfer shuttle which is reciprocally movable along a shuttle path between a sheet application position intersecting the article discharge path and sheet transfer position adjacent to, but spaced from the discharge path. The shuttle has a central opening which encompasses the article discharge path, through which one of the articles may pass freely, when the shuttle is in its application position. The shuttle also has a group of small vacuum grippers which are distributed around the peripheral edges of the central opening in the shuttle, just beyond the edges of an article passing therethrough.
The sheet applicator also has a sheet feeder which includes a releasable sheet holder means for depositing a single, thin, flexible sheet on the shuttle in registry with the shuttle vacuum grippers, whenever the shuttle reaches its sheet transfer position. Each thin, flexible sheet is of a size and configuration so as to cover all of the shuttle vacuum grippers.
The shuttle and the sheet feeder are mechanically linked to, and driven by, the mechanical system that drives the mold plate of the patty-forming apparatus. The shuttle and the sheet feeder are moved in synchronism with the mold plate, with movement of the articles along the discharge path and in synchronism with each other, so that the sheet holder means of the sheet feeder releases each sheet as it arrives at the transfer position in registry with the shuttle vacuum grippers, and so that the shuttle is in its sheet application position each time an article moves therethrough.
This system has been successfully commercialized for many years as a part of the FORMAX F-26 food patty-forming machine, available from Formax, Inc. of Mokena, Ill., U.S.A.
The present inventors have recognized that it would be advantageous to provide an improved sheet interleaving apparatus for a patty-forming apparatus that was not mechanically linked to the patty-forming apparatus for operational movement and that had an increased flexibility of operation and timing.
The present inventors have recognized that it would be advantageous to provide a substantially modular sheet interleaving apparatus that could be added to a patty-forming apparatus easily and cost effectively.
The present inventors have recognized that it would be advantageous to provide a sheet interleaving apparatus for a patty-forming apparatus that reduced overall maintenance requirements by reducing the number of lubrication, sealing and other maintenance points, and by making the maintenance points more accessible.